User input back channel for wireless displays

ABSTRACT

As part of a communication session, a wireless source device can transmit audio and video data to a wireless sink device, and the wireless sink device can transmit user inputs received at the wireless sink device back to the wireless source device. In this manner, a user of the wireless sink device can control the wireless source device and control the content that is being transmitted from the wireless source device to the wireless sink device. As part of establishing the communication session, the wireless sink device and the wireless source device may perform capability negotiation.

This application claims the benefit of

U.S. Provisional Application No. 61/435,194, filed 21 Jan. 2011;

U.S. Provisional Application 61/447,592, filed 28 Feb. 2011;

U.S. Provisional Application 61/448,312, filed 2 Mar. 2011;

U.S. Provisional Application 61/450,101, filed 7 Mar. 2011;

U.S. Provisional Application 61/467,535, filed 25 Mar. 2011;

U.S. Provisional Application 61/467, 543, filed 25 Mar. 2011;

U.S. Provisional Application 61/514,863, filed 3 Aug. 2011; and

U.S. Provisional Application 61/544,445, filed 7 Oct. 2011;

the entire contents each of which are incorporated herein by referencein their entirety.

TECHNICAL FIELD

This disclosure relates to techniques for transmitting data between awireless source device and a wireless sink device.

BACKGROUND

Wireless display (WD) or Wi-Fi Display (WFD) systems include a wirelesssource device and one or more wireless sink devices. The source deviceand each of the sink devices may be either mobile devices or wireddevices with wireless communication capabilities. One or more of thesource device and the sink devices may, for example, include mobiletelephones, portable computers with wireless communication cards,personal digital assistants (PDAs), portable media players, or othersuch devices with wireless communication capabilities, includingso-called “smart” phones and “smart” pads or tablets, e-readers, or anytype of wireless display, video gaming devices, or other types ofwireless communication devices. One or more of the source device and thesink devices may also include wired devices such as televisions, desktopcomputers, monitors, projectors, and the like, that includecommunication capabilities.

The source device sends media data, such as audio video (AV) data, toone or more of the sink devices participating in a particular mediashare session. The media data may be played back at both a local displayof the source device and at each of the displays of the sink devices.More specifically, each of the participating sink devices renders thereceived media data on its screen and audio equipment.

SUMMARY

This disclosure generally describes a system where a wireless sinkdevice can communicate with a wireless sink device. As part of acommunication session, a wireless source device can transmit audio andvideo data to the wireless sink device, and the wireless sink device cantransmit user inputs received at the wireless sink device back to thewireless source device. In this manner, a user of the wireless sinkdevice can control the wireless source device and control the contentthat is being transmitted from the wireless source device to thewireless sink device.

In one example, a method of negotiating capabilities between a wirelesssink device and a wireless source device includes transmitting a messageto the wireless source device, where the message identifies a list ofsupported input categories and a plurality of lists of supported types,where each of the supported input categories of the list of supportedinput categories has an associated list of supported types.

In another example, a wireless sink device is configured to negotiatecapabilities with a wireless source device. The wireless sink deviceincludes a memory storing instructions and one or more processorsconfigured to execute the instructions. Upon execution of theinstructions the one or more processors cause transmitting a message tothe wireless source device, wherein the message identifies a list ofsupported input categories; and a plurality of lists of supported types,wherein each of the supported input categories of the list of supportedinput categories has an associated list of supported types.

In another example, a computer-readable storage medium storesinstructions that upon execution by one or more processors cause the oneor more processors to perform a method of negotiating capabilitiesbetween a wireless sink device and a wireless source device. The methodincludes transmitting a message to the wireless source device, whereinthe message identifies a list of supported input categories and aplurality of lists of supported types, where each of the supported inputcategories of the list of supported input categories has an associatedlist of supported types.

In another example, a wireless sink device is configured to negotiatecapabilities with a wireless source device. The wireless sink deviceincludes means for transmitting a message to the wireless source device,wherein the message identifies a list of supported input categories;and, a plurality of lists of supported types, where each of thesupported input categories of the list of supported input categories hasan associated list of supported types.

In another example, a method of negotiating capabilities between awireless sink device and a wireless source device includes receiving amessage from the wireless sink device, wherein the message identifies alist of supported input categories and a plurality of lists of supportedtypes, where each of the supported input categories of the list ofsupported input categories has an associated list of supported types.

In another example, a wireless source device is configured to negotiatecapabilities with a wireless sink device. The wireless source deviceincludes a memory storing instructions and one or more processorsconfigured to execute the instructions, wherein upon execution of theinstructions the one or more processors cause receiving a message fromthe wireless sink device, wherein the message identifies a list ofsupported input categories and a plurality of lists of supported types,wherein each of the supported input categories of the list of supportedinput categories has an associated list of supported types.

In another example, a computer-readable storage medium storesinstructions that upon execution by one or more processors cause the oneor more processors to perform a method of negotiating capabilitiesbetween a wireless sink device and a wireless source device. The methodincludes receiving a message from the wireless sink device, wherein themessage identifies a list of supported input categories and a pluralityof lists of supported types, wherein each of the supported inputcategories of the list of supported input categories has an associatedlist of supported types.

In another example, a wireless source device is configured to negotiatecapabilities with a wireless sink device. The wireless source deviceincludes means for receiving a message from the wireless sink device,where the message identifies a list of supported input categories and aplurality of lists of supported types, where each of the supported inputcategories of the list of supported input categories has an associatedlist of supported types.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a block diagram illustrating an example of a source/sinksystem that may implement techniques of this disclosure.

FIG. 1B is a block diagram illustrating an example of a source/sinksystem with two sink devices.

FIG. 2 shows an example of a source device that may implement techniquesof this disclosure.

FIG. 3 shows an example of a sink device that may implement techniquesof this disclosure.

FIG. 4 shows a block diagram of a transmitter system and a receiversystem that may implement techniques of this disclosure.

FIGS. 5A and 5B show example message transfer sequences for performingcapability negotiations according to techniques of this disclosure.

FIG. 6 shows an example data packet that may be used for delivering userinput data obtained at a sink device to a source device.

FIGS. 7A and 7B are flow charts illustrating techniques of thisdisclosure that may be used for capability negotiation between a sourcedevice and a sink device.

FIGS. 8A and 8B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packetswith user input data.

FIGS. 9A and 9B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packetswith user input data.

FIGS. 10A and 10B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packetswith timestamp information and user input data.

FIGS. 11A and 11B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packetswith timestamp information and user input data.

FIGS. 12A and 12B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packetsthat include voice commands.

FIGS. 13A and 13B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packetswith multi-touch user input commands.

FIGS. 14A and 14B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packetswith user input data forwarded form a third party device.

FIGS. 15A and 15B are flow charts illustrating techniques of thisdisclosure that may be used for transmitting and receiving data packets.

DETAILED DESCRIPTION

This disclosure generally describes a system where a wireless sinkdevice can communicate with a wireless sink device. As part of acommunication session, a wireless source device can transmit audio andvideo data to the wireless sink device, and the wireless sink device cantransmit user inputs received at the wireless sink device back to thewireless source device. In this manner, a user of the wireless sinkdevice can control the wireless source device and control the contentthat is being transmitted from the wireless source device to thewireless sink device.

FIG. 1A is a block diagram illustrating an exemplary source/sink system100 that may implement one or more of the techniques of this disclosure.As shown in FIG. 1A, system 100 includes source device 120 thatcommunicates with sink device 160 via communication channel 150. Sourcedevice 120 may include a memory that stores audio/video (A/V) data 121,display 122, speaker 123, audio/video encoder 124 (also referred to asencoder 124), audio/video control module 125, and transmitter/receiver(TX/RX) unit 126. Sink device 160 may include display 162, speaker 163,audio/video decoder 164 (also referred to as decoder 164),transmitter/receiver unit 166, user input (UI) device 167, and userinput processing module (UIPM) 168. The illustrated componentsconstitute merely one example configuration for source/sink system 100.Other configurations may include fewer components than those illustratedor may include additional components than those illustrated.

In the example of FIG. 1A, source device 120 can display the videoportion of audio/video data 121 on display 122 and can output the audioportion of audio/video data 121 on speaker 123. Audio/video data 121 maybe stored locally on source device 120, accessed from an externalstorage medium such as a file server, hard drive, external memory,Blu-ray disc, DVD, or other physical storage medium, or may be streamedto source device 120 via a network connection such as the internet. Insome instances audio/video data 121 may be captured in real-time via acamera and microphone of source device 120. Audio/video data 121 mayinclude multimedia content such as movies, television shows, or music,but may also include real-time content generated by source device 120.Such real-time content may for example be produced by applicationsrunning on source device 120, or video data captured, e.g., as part of avideo telephony session. As will be described in more detail, suchreal-time content may in some instances include a video frame of userinput options available for a user to select. In some instances,audio/video data 121 may include video frames that are a combination ofdifferent types of content, such as a video frame of a movie or TVprogram that has user input options overlaid on the frame of video.

In addition to rendering audio/video data 121 locally via display 122and speaker 123, audio/video encoder 124 of source device 120 can encodeaudio/video data 121, and transmitter/receiver unit 126 can transmit theencoded data over communication channel 150 to sink device 160.Transmitter/receiver unit 166 of sink device 160 receives the encodeddata, and audio/video decoder 164 decodes the encoded data and outputsthe decoded data via display 162 and speaker 163. In this manner, theaudio and video data being rendered by display 122 and speaker 123 canbe simultaneously rendered by display 162 and speaker 163. The audiodata and video data may be arranged in frames, and the audio frames maybe time-synchronized with the video frames when rendered.

Audio/video encoder 124 and audio/video decoder 164 may implement anynumber of audio and video compression standards, such as the ITU-T H.264standard, alternatively referred to as MPEG-4, Part 10, Advanced VideoCoding (AVC), or the newly emerging high efficiency video coding (HEVC)standard, sometimes called the H.265 standard. Many other types ofproprietary or standardized compression techniques may also be used.Generally speaking, audio/video decoder 164 is configured to perform thereciprocal coding operations of audio/video encoder 124. Although notshown in FIG. 1A, in some aspects, A/V encoder 124 and A/V decoder 164may each be integrated with an audio encoder and decoder, and mayinclude appropriate MUX-DEMUX units, or other hardware and software, tohandle encoding of both audio and video in a common data stream orseparate data streams.

As will be described in more detail below, A/V encoder 124 may alsoperform other encoding functions in addition to implementing a videocompression standard as described above. For example, A/V encoder 124may add various types of metadata to A/V data 121 prior to A/V data 121being transmitted to sink device 160. In some instances, A/V data 121may be stored on or received at source device 120 in an encoded form andthus not require further compression by A/V encoder 124.

Although, FIG. 1A shows communication channel 150 carrying audio payloaddata and video payload data separately, it is to be understood that insome instances video payload data and audio payload data may be part ofa common data stream. If applicable, MUX-DEMUX units may conform to theITU H.223 multiplexer protocol, or other protocols such as the userdatagram protocol (UDP). Audio/video encoder 124 and audio/video decoder164 each may be implemented as one or more microprocessors, digitalsignal processors (DSPs), application specific integrated circuits(ASICs), field programmable gate arrays (FPGAs), discrete logic,software, hardware, firmware or any combinations thereof. Each ofaudio/video encoder 124 and audio/video decoder 164 may be included inone or more encoders or decoders, either of which may be integrated aspart of a combined encoder/decoder (CODEC). Thus, each of source device120 and sink device 160 may comprise specialized machines configured toexecute one or more of the techniques of this disclosure.

Display 122 and display 162 may comprise any of a variety of videooutput devices such as a cathode ray tube (CRT), a liquid crystaldisplay (LCD), a plasma display, a light emitting diode (LED) display,an organic light emitting diode (OLED) display, or another type ofdisplay device. In these or other examples, the displays 122 and 162 mayeach be emissive displays or transmissive displays. Display 122 anddisplay 162 may also be touch displays such that they are simultaneouslyboth input devices and display devices. Such touch displays may becapacitive, resistive, or other type of touch panel that allows a userto provide user input to the respective device.

Speaker 123 may comprise any of a variety of audio output devices suchas headphones, a single-speaker system, a multi-speaker system, or asurround sound system. Additionally, although display 122 and speaker123 are shown as part of source device 120 and display 162 and speaker163 are shown as part of sink device 160, source device 120 and sinkdevice 160 may in fact be a system of devices. As one example, display162 may be a television, speaker 163 may be a surround sound system, anddecoder 164 may be part of an external box connected, either wired orwirelessly, to display 162 and speaker 163. In other instances, sinkdevice 160 may be a single device, such as a tablet computer orsmartphone. In still other cases, source device 120 and sink device 160are similar devices, e.g., both being smartphones, tablet computers, orthe like. In this case, one device may operate as the source and theother may operate as the sink. These rolls may even be reversed insubsequent communication sessions. In still other cases, the sourcedevice may comprise a mobile device, such as a smartphone, laptop ortablet computer, and the sink device may comprise a more stationarydevice (e.g., with an AC power cord), in which case the source devicemay deliver audio and video data for presentation to a large crowd viathe sink device.

Transmitter/receiver unit 126 and transmitter/receiver unit 166 may eachinclude various mixers, filters, amplifiers and other componentsdesigned for signal modulation, as well as one or more antennas andother components designed for transmitting and receiving data.Communication channel 150 generally represents any suitablecommunication medium, or collection of different communication media,for transmitting video data from source device 120 to sink device 160.Communication channel 150 is usually a relatively short-rangecommunication channel, similar to Wi-Fi, Bluetooth, or the like.However, communication channel 150 is not necessarily limited in thisrespect, and may comprise any wireless or wired communication medium,such as a radio frequency (RF) spectrum or one or more physicaltransmission lines, or any combination of wireless and wired media. Inother examples, communication channel 150 may even form part of apacket-based network, such as a wired or wireless local area network, awide-area network, or a global network such as the Internet.Additionally, communication channel 150 may be used by source device 120and sink device 160 to create a peer-to-peer link. Source device 120 andsink device 160 may communicate over communication channel 150 using acommunications protocol such as a standard from the IEEE 802.11 familyof standards. Source device 120 and sink device 160 may, for example,communicate according to the Wi-Fi Direct standard, such that sourcedevice 120 and sink device 160 communicate directly with one anotherwithout the use of an intermediary such as a wireless access points orso called hotspot. Source device 120 and sink device 160 may alsoestablish a tunneled direct link setup (TLDS) to avoid or reduce networkcongestion. The techniques of this disclosure may at times be describedwith respect to Wi-Fi, but it is contemplated that aspects of thesetechniques may also be compatible with other communication protocols. Byway of example and not limitation, the wireless communication betweensource device 120 and sink device may utilize orthogonal frequencydivision multiplexing (OFDM) techniques. A wide variety of otherwireless communication techniques may also be used, including but notlimited to time division multi access (TDMA), frequency division multiaccess (FDMA), code division multi access (CDMA), or any combination ofOFDM, FDMA, TDMA and/or CDMA. WiFi Direct and TDLS are intended to setuprelatively short-distance communication sessions. Relatively shortdistance in this context may refer to, for example, less than 70 meters,although in a noisy or obstructed environment the distance betweendevices may be even shorter, such as less than 35 meters.

In addition to decoding and rendering data received from source device120, sink device 160 can also receive user inputs from user input device167. User input device 167 may, for example, be a keyboard, mouse,trackball or track pad, touch screen, voice command recognition module,or any other such user input device. UIPM 168 formats user inputcommands received by user input device 167 into a data packet structurethat source device 120 is capable of interpreting. Such data packets aretransmitted by transmitter/receiver 166 to source device 120 overcommunication channel 150. Transmitter/receiver unit 126 receives thedata packets, and A/V control module 125 parses the data packets tointerpret the user input command that was received by user input device167. Based on the command received in the data packet, A/V controlmodule 125 can change the content being encoded and transmitted. In thismanner, a user of sink device 160 can control the audio payload data andvideo payload data being transmitted by source device 120 remotely andwithout directly interacting with source device 120. Examples of thetypes of commands a user of sink device 160 may transmit to sourcedevice 120 include commands for rewinding, fast forwarding, pausing, andplaying audio and video data, as well as commands for zooming, rotating,scrolling, and so on. Users may also make selections, from a menu ofoptions for example, and transmit the selection back to source device120.

Additionally, users of sink device 160 may be able to launch and controlapplications on source device 120. For example, a user of sink device160 may able to launch a photo editing application stored on sourcedevice 120 and use the application to edit a photo that is storedlocally on source device 120. Sink device 160 may present a user with auser experience that looks and feels like the photo is being editedlocally on sink device 160 while in fact the photo is being edited onsource device 120. Using such a configuration, a device user may be ableto leverage the capabilities of one device for use with several devices.For example, source device 120 may be a smartphone with a large amountof memory and high-end processing capabilities. A user of source device120 may use the smartphone in all the settings and situationssmartphones are typically used. When watching a movie, however, the usermay wish to watch the movie on a device with a bigger display screen, inwhich case sink device 160 may be a tablet computer or even largerdisplay device or television. When wanting to send or respond to email,the user may wish to use a device with a keyboard, in which case sinkdevice 160 may be a laptop. In both instances, the bulk of theprocessing may still be performed by source device 120 (a smartphone inthis example) even though the user is interacting with a sink device. Inthis particular operating context, due to the bulk of the processingbeing performed by source device 120, sink device 160 may be a lowercost device with fewer resources than if sink device 160 were beingasked to do the processing being done by source device 120. Both thesource device and the sink device may be capable of receiving user input(such as touch screen commands) in some examples, and the techniques ofthis disclosure may facilitate two way interaction by negotiating and oridentifying the capabilities of the devices in any given session.

In some configuration, A/V control module 125 may be an operating systemprocess being executed by the operating system of source device 125. Inother configurations, however, A/V control module 125 may be a softwareprocess of an application running on source device 120. In such aconfiguration, the user input command may be interpreted by the softwareprocess, such that a user of sink device 160 is interacting directlywith the application running on source device 120, as opposed to theoperating system running on source device 120. By interacting directlywith an application as opposed to an operating system, a user of sinkdevice 160 may have access to a library of commands that are not nativeto the operating system of source device 120. Additionally, interactingdirectly with an application may enable commands to be more easilytransmitted and processed by devices running on different platforms.

Source device 120 can respond to user inputs applied at wireless sinkdevice 160. In such an interactive application setting, the user inputsapplied at wireless sink device 160 may be sent back to the wirelessdisplay source over communication channel 150. In one example, a reversechannel architecture, also referred to as a user interface back channel(UIBC) may be implemented to enable sink device 160 to transmit the userinputs applied at sink device 160 to source device 120. The reversechannel architecture may include upper layer messages for transportinguser inputs and lower layer frames for negotiating user interfacecapabilities at sink device 160 and source device 120. The UIBC mayreside over the Internet Protocol (IP) transport layer between sinkdevice 160 and source device 120. In this manner, the UIBC may be abovethe transport layer in the Open System Interconnection (OSI)communication model. In one example, the OSI communication includesseven layers (1-physical, 2-data link, 3-network, 4-transport,5-session, 6-presentation, and 7-application). In this example, beingabove transport layer refers to layers 5, 6, and 7. To promote reliabletransmission and in sequence delivery of data packets containing userinput data, UIBC may be configured run on top of other packet-basedcommunication protocols such as the transmission controlprotocol/internet protocol (TCP/IP) or the user datagram protocol (UDP).UDP and TCP can operate in parallel in the OSI layer architecture.TCP/IP can enable sink device 160 and source device 120 to implementretransmission techniques in the event of packet loss.

In some cases, there may be a mismatch between the user input interfaceslocated at source device 120 and sink device 160. To resolve thepotential problems created by such a mismatch and to promote a good userexperience under such circumstances, user input interface capabilitynegotiation may occur between source device 120 and sink device 160prior to establishing a communication session or at various timesthroughout a communication session. As part of this negotiation process,source device 120 and sink device 160 can agree on a negotiated screenresolution. When sink device 160 transmits coordinate data associatedwith a user input, sink device 160 can scale coordinate data obtainedfrom display 162 to match the negotiated screen resolution. In oneexample, if sink device 160 has a 1280×720 resolution and source device120 has a 1600×900 resolution, the devices may, for example, use1280×720 as their negotiated resolution. The negotiated resolution maybe chosen based on a resolution of sink device 160, although aresolution of source device 120 or some other resolution may also beused. In the example where the sink device of 1280×720 is used, sinkdevice 160 can scale obtained x-coordinates by a factor of 1600/1280prior to transmitting the coordinates to source device 120, andlikewise, sink device 160 can scale obtained y-coordinates by 900/720prior to transmitting the coordinates to source device 120. In otherconfigurations, source device 120 can scale the obtained coordinates tothe negotiated resolution. The scaling may either increase or decrease acoordinate range based on whether sink device 160 uses a higherresolution display than source device 120, or vice versa.

Additionally, in some instances, the resolution at sink device 160 mayvary during a communication session, potentially creating a mismatchbetween display 122 and display 162. In order to improve the userexperience and to ensure proper functionality, source/sink system 100may implement techniques for reducing or preventing user interactionmismatch by implementing techniques for screen normalization. Display122 of source device 120 and display 162 of sink device 160 may havedifferent resolutions and/or different aspects ratios. Additionally, insome settings, a user of sink device 160 may have the ability to resizea display window for the video data received from source device 120 suchthat the video data received from source device 120 is rendered in awindow that covers less than all of display 162 of sink device 160. Inanother example setting, a user of sink device 160 may have the optionof viewing content in either a landscape mode or a portrait mode, eachof which has unique coordinates and different aspect ratios. In suchsituations, coordinates associated with a user input received at sinkdevice 160, such as the coordinate for where a mouse click or touchevent occurs, may not able to be processed by source device 120 withoutmodification to the coordinates. Accordingly, techniques of thisdisclosure may include mapping the coordinates of the user inputreceived at sink device 160 to coordinates associated with source device120. This mapping is also referred to as normalization herein, and aswill be explained in greater detail below, this mapping can be eithersink-based or source-based.

User inputs received by sink device 160 can be received by UI module167, at the driver level for example, and passed to the operating systemof sink device 160. The operating system on sink device 160 can receivecoordinates (x_(SINK), y_(SINK)) associated with where on a displaysurface a user input occurred. In this example, (x_(SINK), y_(SINK)) canbe coordinates of display 162 where a mouse click or a touch eventoccurred. The display window being rendered on display 162 can have anx-coordinate length (L_(DW)) and a y-coordinate width (W_(DW)) thatdescribe the size of the display window. The display window can alsohave an upper left corner coordinate (a_(DW), b_(DW)) that describes thelocation of the display window. Based on L_(DW), W_(DW), and the upperleft coordinate (a_(DW), b_(DW)), the portion of display 162 covered bythe display window can be determined. For example, an upper right cornerof the display window can be located at coordinate (a_(DW)+L_(DW),b_(DW)), a lower left corner of the display window can be located atcoordinate (a_(DW), b_(DW)+W_(DW)), and a lower right corner of thedisplay window can be located at coordinate (a_(DW)+L_(DW),b_(DW)+W_(DW)). Sink device 160 can process an input as a UIBC input ifthe input is received at a coordinate within the display window. Inother words, an input with associated coordinates (x_(SINK), y_(SINK))can be processed as a UIBC input if the following conditions are met:a _(DW) ≦x _(SINK) ≦a _(DW) +L _(DW)  (1)b _(DW) ≦y _(SINK) ≦b _(DW) +W _(DW)  (2)

After determining that a user input is a UIBC input, coordinatesassociated with the input can be normalized by UIPM 168 prior to beingtransmitted to source device 120. Inputs that are determined to beoutside the display window can be processed locally by sink device 160as non-UIBC inputs.

As mentioned above, the normalization of input coordinates can be eithersourced-based or sink-based. When implementing sink-based normalization,source device 120 can send a supported display resolution (L_(SRC),W_(SRC)) for display 122, either with video data or independently ofvideo data, to sink device 160. The supported display resolution may,for example, be transmitted as part of a capability negotiation sessionor may be transmitted at another time during a communication session.Sink device 160 can determine a display resolution (L_(SINK), W_(SINK))for display 162, the display window resolution (L_(DW), W_(DW)) for thewindow displaying the content received from source device 120, and theupper left corner coordinate (a_(DW), b_(DW)) for the display window. Asdescribed above, when a coordinate (x_(SINK), y_(SINK)) corresponding toa user input is determined to be within the display window, theoperating system of sink device 160 can map the coordinate (x_(SINK),y_(SINK)) to source coordinates (x_(SRC), y_(SRC)) using conversionfunctions. Example conversion functions for converting (x_(SINK),y_(SINK)) to (x_(SRC), y_(SRC)) can be as follows:x _(SRC)=(x _(SINK) −a _(DW))*(L _(SRC) /L _(DW))  (3)y _(SRC)=(y _(SINK) −b _(DW))*(W _(SRC) /W _(DW))  (4)

Thus, when transmitting a coordinate corresponding to a received userinput, sink device 160 can transmit the coordinate (x_(SRC), y_(SRC))for a user input received at (x_(SINK), y_(SINK)). As will be describedin more detail below, coordinate (x_(SRC), y_(SRC)) may, for example, betransmitted as part of a data packet used for transmitting user inputreceived at sink device 160 to source device 120 over the UIBC.Throughout other portions of this disclosure, where input coordinatesare described as being included in a data packet, those coordinates canbe converted to source coordinates as described above in instances wheresource/sink system 100 implements sink-based normalization.

When source/sink system 100 implements sourced-based normalization, foruser inputs determined to by UIBC inputs as opposed to local inputs(i.e. within a display window as opposed to outside a display window),the calculations above can be performed at source device 120 instead ofsink device 160. To facilitate such calculations, sink device 160 cantransmit to source device 120 values for L_(DW), W_(DW), and locationinformation for the display window (e.g. a_(DW), b_(DW)), as well ascoordinates for (x_(SINK), y_(SINK)). Using these transmitted values,source device 120 can determine values for (x_(SRC), y_(SRC)) accordingto equations 3 and 4 above.

In other implementations of sink-based normalization, sink device 160can transmit coordinates (x_(DW), y_(DW)) for a user input that describewhere within the display window a user input event occurs as opposed towhere on display 162 the user input even occurs. In such animplementation, coordinates (x_(DW), y_(DW)) can be transmitted tosource device 120 along with values for (L_(DW), W_(DW)). Based on thesereceived values, source device 120 can determine (x_(SRC), y_(SRC))according to the following conversion functions:x _(SRC) =x _(DW)*(L _(SRC) /L _(DW))  (5)y _(SRC) =y _(DW)*(W _(SRC) /W _(DW))  (6)Sink device 160 can determine x_(DW) and y_(DW) based on the followingfunctions:x _(DW) =x _(SINK) −a _(DW)  (7)y _(DW) =y _(SINK) −b _(DW)  (8)

When this disclosure describes transmitting coordinates associated witha user input, in a data packet for example, the transmission of thesecoordinates may include sink-based or source-based normalization asdescribed above, and/or may include any additional information necessaryfor performing the sink-based or source-based normalization.

The UIBC may be designed to transport various types of user input data,including cross-platform user input data. For example, source device 120may run the iOS® operating system, while sink device 160 runs anotheroperating system such as Android® or Windows®. Regardless of platform,UIPM 168 can encapsulate received user input in a form understandable toA/V control module 125. A number of different types of user inputformats may be supported by the UIBC so as to allow many different typesof source and sink devices to exploit the protocol regardless of whetherthe source and sink devices operate on different platforms. Genericinput formats may be defined, and platform specific input formats mayboth be supported, thus providing flexibility in the manner in whichuser input can be communicated between source device 120 and sink device160 by the UIBC.

In the example of FIG. 1A, source device 120 may comprise a smartphone,tablet computer, laptop computer, desktop computer, Wi-Fi enabledtelevision, or any other device capable of transmitting audio and videodata. Sink device 160 may likewise comprise a smartphone, tabletcomputer, laptop computer, desktop computer, Wi-Fi enabled television,or any other device capable of receiving audio and video data andreceiving user input data. In some instances, sink device 160 mayinclude a system of devices, such that display 162, speaker 163, UIdevice 167, and A/V encoder 164 all parts of separate but interoperativedevices. Source device 120 may likewise be a system of devices ratherthan a single device.

In this disclosure, the term source device is generally used to refer tothe device that is transmitting audio/video data, and the term sinkdevice is generally used to refer to the device that is receiving theaudio/video data from the source device. In many cases, source device120 and sink device 160 may be similar or identical devices, with onedevice operating as the source and the other operating as the sink.Moreover, these rolls may be reversed in different communicationsessions. Thus, a sink device in one communication session may become asource device in a subsequent communication session, or vice versa.

FIG. 1B is a block diagram illustrating an exemplary source/sink system101 that may implement techniques of this disclosure. Source/sink system101 includes source device 120 and sink device 160, each of which mayfunction and operate in the manner described above for FIG. 1A.Source/sink system 101 further includes sink device 180. In a similarmanner to sink device 160 described above, sink device 180 may receiveaudio and video data from source device 120 and transmit user commandsto source device 120 over an established UIBC. In some configurations,sink device 160 and sink device 180 may operate independently of oneanother, and audio and video data output at source device 120 may besimultaneously output at sink device 160 and sink device 180. Inalternate configurations, sink device 160 may be a primary sink deviceand sink device 180 may be a secondary sink device. In such an exampleconfiguration, sink device 160 and sink device 180 may be coupled, andsink device 160 may display video data while sink device 180 outputscorresponding audio data. Additionally, in some configurations, sinkdevice 160 may output transmitted video data only while sink device 180outputs transmitted audio data only.

FIG. 2 is a block diagram showing one example of a source device 220.Source device 220 may be a device similar to source device 120 in FIG.1A and may operate in the same manner as source device 120. Sourcedevice 220 includes local display 222, local speaker 223, processors231, memory 232, transport unit 233, and wireless modem 234. As shown inFIG. 2, source device 220 may include one or more processors (i.e.processor 231) that encode and/or decode A/V data for transport,storage, and display. The A/V data may for example be stored at memory232. Memory 232 may store an entire A/V file, or may comprise a smallerbuffer that simply stores a portion of an A/V file, e.g., streamed fromanother device or source. Transport unit 233 may process encoded A/Vdata for network transport. For example, encoded A/V data may beprocessed by processor 231 and encapsulated by transport unit 233 intoNetwork Access Layer (NAL) units for communication across a network. TheNAL units may be sent by wireless modem 234 to a wireless sink devicevia a network connection. Wireless modem 234 may, for example, be aWi-Fi modem configured to implement one of the IEEE 802.11 family ofstandards.

Source device 220 may also locally process and display A/V data. Inparticular display processor 235 may process video data to be displayedon local display 222, audio processor 236 may process audio data foroutput on speaker 223.

As described above with reference to source device 120 of FIG. 1A,source device 220 may also receive user input commands from a sinkdevice. In this manner, wireless modem 234 of source device 220 receivesencapsulated data packets, such as NAL units, and sends the encapsulateddata units to transport unit 233 for decapsulation. For instance,transport unit 233 may extract data packets from the NAL units, andprocessor 231 can parse the data packets to extract the user inputcommands. Based on the user input commands, processor 231 can adjust theencoded A/V data being transmitted by source device 220 to a sinkdevice. In this manner, the functionality described above in referenceto A/V control module 125 of FIG. 1A may be implemented, either fully orpartially, by processor 231.

Processor 231 of FIG. 2 generally represents any of a wide variety ofprocessors, including but not limited to one or more digital signalprocessors (DSPs), general purpose microprocessors, application specificintegrated circuits (ASICs), field programmable logic arrays (FPGAs),other equivalent integrated or discrete logic circuitry, or somecombination thereof. Memory 232 of FIG. 2 may comprise any of a widevariety of volatile or non-volatile memory, including but not limited torandom access memory (RAM) such as synchronous dynamic random accessmemory (SDRAM), read-only memory (ROM), non-volatile random accessmemory (NVRAM), electrically erasable programmable read-only memory(EEPROM), FLASH memory, and the like, Memory 232 may comprise acomputer-readable storage medium for storing audio/video data, as wellas other kinds of data. Memory 232 may additionally store instructionsand program code that are executed by processor 231 as part ofperforming the various techniques described in this disclosure.

FIG. 3 shows an example of a sink device 360. Sink device 360 may be adevice similar to sink device 160 in FIG. 1A and may operate in the samemanner as sink device 160. Sink device 360 includes one or moreprocessors (i.e. processor 331), memory 332, transport unit 333,wireless modem 334, display processor 335, local display 362, audioprocessor 336, speaker 363, and user input interface 376. Sink device360 receives at wireless modem 334 encapsulated data units sent from asource device. Wireless modem 334 may, for example, be a Wi-Fi modemconfigured to implement one more standards from the IEEE 802.11 familyof standards. Transport unit 333 can decapsulate the encapsulated dataunits. For instance, transport unit 333 may extract encoded video datafrom the encapsulated data units and send the encoded A/V data toprocessor 331 to be decoded and rendered for output. Display processor335 may process decoded video data to be displayed on local display 362,and audio processor 336 may process decoded audio data for output onspeaker 363.

In addition to rendering audio and video data, wireless sink device 360can also receive user input data through user input interface 376. Userinput interface 376 can represent any of a number of user input devicesincluded but not limited to a touch display interface, a keyboard, amouse, a voice command module, gesture capture device (e.g., withcamera-based input capturing capabilities) or any other of a number ofuser input devices. User input received through user input interface 376can be processed by processor 331. This processing may includegenerating data packets that include the received user input command inaccordance with the techniques described in this disclosure. Oncegenerated, transport unit 333 may process the data packets for networktransport to a wireless source device over a UIBC.

Processor 331 of FIG. 3 may comprise one or more of a wide range ofprocessors, such as one or more digital signal processors (DSPs),general purpose microprocessors, application specific integratedcircuits (ASICs), field programmable logic arrays (FPGAs), otherequivalent integrated or discrete logic circuitry, or some combinationthereof. Memory 332 of FIG. 3 may comprise any of a wide variety ofvolatile or non-volatile memory, including but not limited to randomaccess memory (RAM) such as synchronous dynamic random access memory(SDRAM), read-only memory (ROM), non-volatile random access memory(NVRAM), electrically erasable programmable read-only memory (EEPROM),FLASH memory, and the like, Memory 232 may comprise a computer-readablestorage medium for storing audio/video data, as well as other kinds ofdata. Memory 332 may additionally store instructions and program codethat are executed by processor 331 as part of performing the varioustechniques described in this disclosure.

FIG. 4 shows a block diagram of an example transmitter system 410 andreceiver system 450, which may be used by transmitter/receiver 126 andtransmitter/receiver 166 of FIG. 1A for communicating over communicationchannel 150. At transmitter system 410, traffic data for a number ofdata streams is provided from a data source 412 to a transmit (TX) dataprocessor 414. Each data stream may be transmitted over a respectivetransmit antenna. TX data processor 414 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream.

The coded data for each data stream may be multiplexed with pilot datausing orthogonal frequency division multiplexing (OFDM) techniques. Awide variety of other wireless communication techniques may also beused, including but not limited to time division multi access (TDMA),frequency division multi access (FDMA), code division multi access(CDMA), or any combination of OFDM, FDMA, TDMA and/or CDMA.

Consistent with FIG. 4, the pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (e.g., symbol mapped) basedon a particular modulation scheme (e.g., Binary Phase Shift Keying(BPSK), Quadrature Phase Shift Keying (QPSK), M-PSK, or M-QAM(Quadrature Amplitude Modulation), where M may be a power of two)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 430 which may be coupled with memory432.

The modulation symbols for the data streams are then provided to a TXMIMO processor 420, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 420 can then provide N_(T)modulation symbol streams to N_(T) transmitters (TMTR) 422 a through 422t. In certain aspects, TX MIMO processor 420 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 422 may receive and process a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 422 a through 422 t are thentransmitted from N_(T) antennas 424 a through 424 t, respectively.

At receiver system 450, the transmitted modulated signals are receivedby N_(R) antennas 452 a through 452 r and the received signal from eachantenna 452 is provided to a respective receiver (RCVR) 454 a through454 r. Receiver 454 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

A receive (RX) data processor 460 then receives and processes the N_(R)received symbol streams from N_(R) receivers 454 based on a particularreceiver processing technique to provide N_(T) “detected” symbolstreams. The RX data processor 460 then demodulates, deinterleaves anddecodes each detected symbol stream to recover the traffic data for thedata stream. The processing by RX data processor 460 is complementary tothat performed by TX MIMO processor 420 and TX data processor 414 attransmitter system 410.

A processor 470 that may be coupled with a memory 472 periodicallydetermines which pre-coding matrix to use. The reverse link message maycomprise various types of information regarding the communication linkand/or the received data stream. The reverse link message is thenprocessed by a TX data processor 438, which also receives traffic datafor a number of data streams from a data source 436, modulated by amodulator 480, conditioned by transmitters 454 a through 454 r, andtransmitted back to transmitter system 410.

At transmitter system 410, the modulated signals from receiver system450 are received by antennas 424, conditioned by receivers 422,demodulated by a demodulator 440, and processed by a RX data processor442 to extract the reserve link message transmitted by the receiversystem 450. Processor 430 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

FIG. 5A is a block diagram illustrating an example message transfersequence between a source device 520 and a sink device 560 as part of acapabilities negotiations session. Capability negotiation may occur aspart of a larger communication session establishment process betweensource device 520 and sink device 560. This session may, for example, beestablished with Wi-Fi Direct or TDLS as the underlying connectivitystandard. After establishing the Wi-Fi Direct or TDLS session, sinkdevice 560 can initiate a TCP connection with source device 520. As partof establishing the TCP connection, a control port running a real timestreaming protocol (RTSP) can be established to manage a communicationsession between source device 520 and sink device 560.

Source device 520 may generally operate in the same manner describedabove for source device 120 of FIG. 1A, and sink device 560 maygenerally operate in the same manner described above for sink device 160of FIG. 1A. After source device 520 and sink device 560 establishconnectivity, source device 520 and sink device 560 may determine theset of parameters to be used for their subsequent communication sessionas part of a capability negotiation exchange.

Source device 520 and sink device 560 may negotiate capabilities througha sequence of messages. The messages may, for example, be real timestreaming protocol (RTSP) messages. At any stage of the negotiations,the recipient of an RTSP request message may respond with an RTSPresponse that includes an RTSP status code other than RTSP OK, in whichcase, the message exchange might be retried with a different set ofparameters or the capability negotiation session may be ended.

Source device 520 can send a first message (RTSP OPTIONS requestmessage) to sink device 560 in order to determine the set of RTSPmethods that sink device 560 supports. On receipt of the first messagefrom source device 520, sink device 560 can respond with a secondmessage (RTSP OPTIONS response message) that lists the RTSP methodssupported by sink 560. The second message may also include a RTSP OKstatus code.

After sending the second message to source device 520, sink device 560can send a third message (RTSP OPTIONS request message) in order todetermine the set of RTSP methods that source device 520 supports. Onreceipt of the third message from sink device 560, source device 520 canrespond with a fourth message (RTSP OPTIONS response message) that liststhe RTSP methods supported by source device 520. The fourth message canalso include RTSP OK status code.

After sending the fourth message, source device 520 can send a fifthmessage (RTSP GET_PARAMETER request message) to specify a list ofcapabilities that are of interest to source device 520. Sink device 560can respond with a sixth message (an RTSP GET_PARAMETER responsemessage). The sixth message may contain an RTSP status code. If the RTSPstatus code is OK, then the sixth message can also include responseparameters to the parameter specified in the fifth message that aresupported by sink device 560. Sink device 560 can ignore parameters inthe fifth message that sink device 560 does not support.

Based on the sixth message, source 520 can determine the optimal set ofparameters to be used for the communication session and can send aseventh message (an RTSP SET_PARAMETER request message) to sink device560. The seventh message can contain the parameter set to be used duringthe communication session between source device 520 and sink device 560.The seventh message can include the wfd-presentation-url that describesthe Universal Resource Identifier (URI) to be used in the RTSP Setuprequest in order to setup the communication session. Thewfd-presentation-url specifies the URI that sink device 560 can use forlater messages during a session establishment exchange. The wfd-url0 andwfd-url1 values specified in this parameter can correspond to the valuesof rtp-port0 and rtp-port1 values in the wfd-client-rtp-ports in theseventh message. RTP in this instance generally refers to the real-timeprotocol which can run on top of the UDP.

Upon receipt of the seventh message, sink device 560 can respond with aneighth message with an RTSP status code indicating if setting theparameters as specified in the seventh message was successful. Asmentioned above, the roles or source device and sink device may reverseor change in different sessions. The order of the messages that set upthe communication session may, in some cases, define the device thatoperates as the source and define the device that operates as the sink.

FIG. 5B is a block diagram illustrating another example message transfersequence between a source device 560 and a sink device 520 as part ofcapabilities negotiations session. The message transfer sequence of FIG.5B is intended provide a more detailed view of the transfer sequencedescribed above for FIG. 5A. In FIG. 5B, message “1 b. GET_PARAMETERRESPONSE” shows an example of a message that identifies a list ofsupported input categories (e.g. generic and HIDC) and a plurality oflists of supported input types. Each of the supported input categoriesof the list of supported input categories has an associated list ofsupported types (e.g. generic_cap_list and hidc_cap_list). In FIG. 5B,message “2 a. SET_PARAMETER REQUEST” is an example of a second messagethat identifies a second list of supported input categories (e.g.generic and HIDC), and a plurality of second lists of supported types.Each of the supported input categories of the second list of supportedinput categories has an associated second list of supported types (e.g.generic_cap_list and hidc_cap_list). Message “1 b. GET_PARAMETERRESPONSE” identifies the input categories and input types supported bysink device 560. Message “2 a. SET_PARAMETER REQUEST” identifies inputcategories and input types supported by source device 520, but it maynot be a comprehensive list of all input categories and input typessupported by source device 520. Instead, message “2 a. SET_PARAMETERREQUEST” may identify only those input categories and input typesidentified in message “1 b. GET_PARAMETER RESPONSE” as being supportedby sink device 560. In this manner, the input categories and input typesidentified in message “2 a. SET_PARAMETER REQUEST” may constitute asubset of the input categories and input types identified in message “1b. GET_PARAMETER RESPONSE.”

FIG. 6 is a conceptual diagram illustrating one example of a data packetthat may be generated by a sink device and transmitted to a sourcedevice. Aspects of data packet 600 will be explained with reference toFIG. 1A, but the techniques discussed may be applicable to additionaltypes of source/sink systems. Data packet 600 may include a data packetheader 610 followed by payload data 650. Payload data 650 mayadditionally include one or more payload headers (e.g. payload header630). Data packet 600 may, for example, be transmitted from sink device160 of FIG. 1A to source device 120, such that a user of sink device 160can control audio/video data being transmitted by source device 120. Insuch an instance, payload data 650 may include user input data receivedat sink device 160. Payload data 650 may, for example, identify one ormore user commands. Sink device 160 can receive the one or more usercommands, and based on the received commands, can generate data packetheader 610 and payload data 650. Based on the content of data packetheader 610 of data packet 600, source device 120 can parse payload data650 to identify the user input data received at sink device 160. Basedon the user input data contained in payload data 650, source device 120may alter in some manner the audio and video data being transmitted fromsource device 120 to sink device 160.

As used in this disclosure, the terms “parse” and “parsing” generallyrefer to the process of analyzing a bitstream to extract data from thebitstream. Once extracted, the data can be processed by source device120, for example. Extracting data may, for example, include identifyinghow information in the bitstream is formatted. As will be described inmore detail below, data packet header 610 may define a standardizedformat that is known to both source device 120 and sink device 160.Payload data 650, however, may be formatted in one of many possibleways. By parsing data packet header 610, source device 120 can determinehow payload data 650 is formatted, and thus, source device 120 can parsepayload data 650 to extract from payload data 650 one or more user inputcommands. This can provide flexibility in terms of the different typesof payload data that can be supported in source-sink communication. Aswill be described in more detail below, payload data 650 may alsoinclude one or more payload headers such as payload header 630. In suchinstances, source device 120 may parse data packet header 610 todetermine a format for payload header 630, and then parse payload header630 to determine a format for the remainder of payload data 650.

Diagram 620 is a conceptual depiction of how data packet header 610 maybe formatted. The numbers 0-15 in row 615 are intended to identify bitlocations within data packet header 610 and are not intended to actuallyrepresent information contained within data packet header 610. Datapacket header 610 includes version field 621, timestamp flag 622,reserved field 623, input category field 624, length field 625, andoptional timestamp field 626.

In the example of FIG. 6, version field 621 is a 3-bit field that mayindicate the version of a particular communications protocol beingimplemented by sink device 160. The value in version field 621 mayinform source device 120 how to parse the remainder of data packetheader 610 as well as how to parse payload data 650. In the example ofFIG. 6, version field 621 is a three-bit field, which would enable aunique identifier for eight different versions. In other examples, moreor fewer bits may be dedicated to version field 621.

In the example of FIG. 6, timestamp flag (T) 622 is a 1-bit field thatindicates whether or not timestamp field 626 is present in data packetheader 610. Timestamp field 626 is a 16-bit field containing a timestampbased on multimedia data that was generated by source device 120 andtransmitted to sink device 160. The timestamp may, for example, be asequential value assigned to frames of video by source device 120 priorto the frames being transmitted to sink device 160. Timestamp flag 622may, for example, include a “1” to indicate timestamp field 626 ispresent and may include a “0” to indicate timestamp field 626 is notpresent. Upon parsing data packet header 610 and determining thattimestamp field 626 is present, source device 120 can process thetimestamp included in timestamp field 626. Upon parsing data packetheader 610 and determining that timestamp field 626 is not present,source device 120 may begin parsing payload data 650 after parsinglength field 625, as no timestamp field is present in data packet header610.

If present, timestamp field 626 can include a timestamp to identify aframe of video data that was being displayed at wireless sink device 160when the user input data of payload data 650 was obtained. The timestampmay, for example, have been added to the frame of video by source device120 prior to source device 120 transmitting the frame of video to sinkdevice 160. Accordingly, source device 120 may generate a frame of videoand embed in the video data of the frame, as metadata for example, atimestamp. Source device 120 can transmit the video frame, with thetimestamp, to sink device 160, and sink device 160 can display the frameof video. While the frame of video is being displayed by sink device160, sink device 160 can receive a user command from a user. When sinkdevice 160 generates a data packet to transfer the user command tosource device 120, sink device 160 can include in timestamp field 626the timestamp of the frame that was being displayed by sink device 160when the user command was received.

Upon receiving data packet 600 with timestamp field 626 present in theheader, wireless source device 120 may identify the frame of video beingdisplayed at sink device 160 at the time the user input data of payloaddata 650 was obtained and process the user input data based on thecontent of the frame identified by the timestamp. For example, if theuser input data is a touch command applied to a touch display or a clickof a mouse pointer, source device 120 can determine the content of theframe being displayed at the time the user applied the touch command tothe display or clicked the mouse. In some instances, the content of theframe may be needed to properly process the payload data. For example, auser input based on a user touch or a mouse click can be dependent onwhat was being shown on the display at the time of the touch or theclick. The touch or click may, for example, correspond to an icon ormenu option. In instances where the content of the display is changing,a timestamp present in timestamp field 626 can be used by source device120 to match the touch or click to the correct icon or menu option.

Source device 120 may additionally or alternatively, compare thetimestamp in timestamp field 626 to a timestamp being applied to acurrently rendered frame of video. By comparing the timestamp oftimestamp field 626 to a current timestamp, source device 120 candetermine a round trip time. The round trip time generally correspondsto the amount of time that lapses from the point when a frame istransmitted by source device 120 to the point when a user input based onthat frame is received back at source device 120 from sink device 160.The round trip time can provide source device 120 with an indication ofsystem latency, and if the round trip time is greater than a thresholdvalue, then source device 120 may ignore the user input data containedin payload data 650 under the assumption the input command was appliedto an outdated display frame. When the round trip time is less than thethreshold, source device 120 may process the user input data and adjustthe audio/video content being transmitted in response to the user inputdata. Thresholds may be programmable, and different types of devices (ordifferent source-sink combinations) may be configured to definedifferent thresholds for round trip times that are acceptable.

In the example of FIG. 6, reserved field 623 is an 8-bit field that doesnot include information used by source 120 in parsing data packet header610 and payload data 650. Future versions of a particular protocol (asidentified in version field 621), however, may make use of reservedfield 623, in which case source device 120 may use information inreserved field 623 for parsing data packet header 610 and/or for parsingpayload data 650. Reserved field 623 in conjunction with version field621 potentially provide capabilities for expanding and adding featuresto the data packet format without fundamentally altering the format andfeatures already in use.

In the example of FIG. 6, input category field 624 is a 4-bit field toidentify an input category for the user input data contained in payloaddata 650. Sink device 160 may categorize the user input data todetermine an input category. Categorizing user input data may, forexample, be based on the device from which a command is received orbased on properties of the command itself. The value of input categoryfield 624, possibly in conjunction with other information of data packetheader 610, identifies to source device 120 how payload data 650 isformatted. Based on this formatting, source device 120 can parse payloaddata 650 to determine the user input that was received at sink device160.

As input category 624, in the example of FIG. 6, is 4 bits, sixteendifferent input categories could possibly be identified. One such inputcategory may be a generic input format to indicate that the user inputdata of payload data 650 is formatted using generic information elementsdefined in a protocol being executed by both source device 120 and sinkdevice 160. A generic input format, as will be described in more detailbelow, may utilize generic information elements that allow for a user ofsink device 160 to interact with source device 120 at the applicationlevel.

Another such input category may be a human interface device command(HIDC) format to indicate that the user input data of payload data 650is formatted based on the type of input device used to receive the inputdata. Examples of types of devices include a keyboard, mouse, touchinput device, joystick, camera, gesture capturing device (such as acamera-based input device), and remote control. Other types of inputcategories that might be identified in input category field 624 includea forwarding input format to indicate user data in payload data 650 didnot originate at sink device 160, or an operating system specificformat, and a voice command format to indicate payload data 650 includesa voice command.

Length field 625 may comprise a 16-bit field to indicate the length ofdata packet 600. The length may, for example, be indicated in units of8-bits. As data packet 600 is parsed by source device 120 in words of 16bits, data packet 600 can be padded up to an integer number of 16 bits.Based on the length contained in length field 625, source device 120 canidentify the end of payload data 650 (i.e. the end of data packet 600)and the beginning of a new, subsequent data packet.

The various sizes of the fields provided in the example of FIG. 6 aremerely intended to be explanatory, and it is intended that the fieldsmay be implemented using different numbers of bits than what is shown inFIG. 6. Additionally, it is also contemplated that data packet header610 may include fewer than all the fields discussed above or may useadditional fields not discussed above. Indeed, the techniques of thisdisclosure may be flexible, in terms of the actual format used for thevarious data fields of the packets.

After parsing data packet header 610 to determine a formatting ofpayload data 650, source device 120 can parse payload data 650 todetermine the user input command contained in payload data 650. Payloaddata 650 may have its own payload header (payload header 630) indicatingthe contents of payload data 650. In this manner, source device 120 mayparse payload header 630 based on the parsing of data packet header 610,and then parse the remainder payload data 650 based on the parsing ofthe payload header 630.

If, for example, input category field 624 of data packet header 610indicates a generic input is present in payload data 650, then payloaddata 650 can have a generic input format. Source device 120 can thusparse payload data 650 according to the generic input format. As part ofthe generic input format, payload data 650 can include a series of oneor more input events with each input event having its own input eventheader. Table 1, below identifies the fields that may be included in aninput header.

TABLE 1 Field Size (Octet) Value Generic IE ID 1 See Table 2 Length 2Length of the following fields in octets Describe Variable The detailsof the user inputs. See Tables

The generic input event (IE) identification (ID) field identifies thegeneric input event identification for identifying an input type. Thegeneric IE ID field may, for example, be one octet in length and mayinclude an identification selected from Table 2 below. If, as in thisexample, the generic IE ID field is 8 bits, then 256 different types ofinputs (identified 0-255) may be identifiable, although not all 256identifications necessarily need an associated input type. Some of the256 may be reserved for future use with future versions of whateverprotocol is being implemented by sink device 160 and source device 120.In Table 2, for instance, generic IE IDs 9-255 do not have associatedinput types but could be assigned input types in the future.

The length field in the input event header identifies the length of thedescribe field while the describe field includes the informationelements that describe the user input. The formatting of the describefield may be dependent on the type of input identifies in the generic IEID field. Thus, source device 120 may parse the contents of the describefield based on the input type identified in the generic IE ID field.Based on the length field of the input event header, source device 120can determine the end of one input event in payload data 650 and thebeginning of a new input event. As will be explained in more detailbelow, one user command may be described in payload data 650 as one ormore input events.

Table 2 provides an example of input types, each with a correspondinggeneric IE ID that can be used for identifying the input type.

TABLE 2 Generic IE ID INPUT TYPE 0 Left Mouse Down/Touch Down 1 LeftMouse Up/Touch Up 2 Mouse Move/Touch Move 3 Key Down 4 Key Up 5 Zoom 6Vertical Scroll 7 Horizontal Scroll 8 Rotate   9-255 Reserved

The describe fields associated with each input type may have a differentformat. The describe fields of a LeftMouse Down/TouchDown event, a LeftMouse Up/Touch Up event, and Mouse Move/Touch Move event may, forexample, include the information elements identified in Table 3 below,although other formats could also be used in other examples.

TABLE 3 Field Size (Octet) Notes Number of 1 Number of pointers of amulti- pointers (N) touch motion event. When set to 1, it indicates asingle-touch motion event. For i = 1: N { Pointer ID 1 Theidentification number of this pointer. The value lies in [0,1, . . . ]X-coordinate 2 X-coordinate for the event normalized with respect to anegotiated resolution of a video stream between sink device and sourcedevice. Y-coordinate} 2 Y-coordinate for the event normalized withrespect to a negotiated resolution of a video stream between sink deviceand source device.

The number of pointers may identify the number of touches or mouseclicks associated with an input event. Each pointer may have a uniquepointer ID. If, for example, a multi-touch event includes a three fingertouch, then the input event might have three pointers, each with aunique pointer ID. Each pointer (i.e. each finger touch) may have acorresponding x-coordinate and y-coordinate corresponding to where thetouch occurred.

A single user command may be described as a series of input events. Forexample, if a three-finger swipe is a command to close an application,the three finger swipe may be described in payload data 650 as a touchdown event with three pointers, a touch move event with three pointers,and a touch up event with three pointers. The three pointers of thetouch down event may have the same pointer IDs as the three pointers ofthe touch move event and touch up event. Source device 120 can interpretthe combination of those three input events as a three finger swipe.

The describe fields of a Key Down event or a Key Up event may, forexample, include the information elements identified in Table 4 below.

TABLE 4 Field Size (Octet) Notes Reserved 1 Reserved Key code 2 The keycode of the first key down or up 1 (ASCII) event. The basic/extendedASCII code uses the lower one byte. The higher one byte is reserved forfuture ASCII compatible key code Key code 2 The key code for the secondkey down or up 2 (ASCII) event. The basic/extended ASCII code uses thelower one byte. The higher one byte is reserved for future ASCIIcompatible key code.

The describe field of a zoom event may, for example, include theinformation elements identified in Table 5 below.

TABLE 5 Field Size (Octet) Notes X 2 The reference X-coordinate for thezoom operation normalized with respect to with respect to a negotiatedresolution of a video stream between sink device and source device. Y 2The reference Y-coordinate for the zoom operation normalized withrespect to with respect to a negotiated resolution of a video streambetween sink device and source device. Integer times 1 The unsignedinteger portion of the to zoom number of times to zoom Fraction times 1The fraction portion of the number of to zoom times to zoom

The describe field of a horizontal scroll event or a vertical scrollevent may, for example, include the information elements identified inTable 6 below.

TABLE 6 Field Size(Octet) Notes Amount 2 Number of pixels to scrollnormalized with to scroll respect to a negotiated resolution of a videostream between sink device and source device. A negative number canindicate to scroll right, and a positive number can indicate to scrollleft

The above examples have shown some exemplary ways that the payload datamight be formatted for a generic input category. If input category field624 of data packet header 610 indicates a different input category, suchas a forwarded user input, then payload data 650 can have a differentinput format. With a forwarded user input, sink device 160 may receivethe user input data from a third party device and forward the input tosource device 120 without interpreting the user input data. Sourcedevice 120 can thus parse payload data 650 according to the forwardeduser input format. For example, payload header 630 of payload data 650may include a field to identify the third party device from which theuser input was obtained. The field may, for example, include an internetprotocol (IP) address of the third party device, MAC address, a domainname, or some other such identifier. Source device 120 can parse theremainder of the payload data based on the identifier of the third partydevice.

Sink device 160 can negotiate capabilities with the third party devicevia a series of messages. Sink device 160 can then transmit a uniqueidentifier of the third party device to source device 120 as part ofestablishing a communication session with source device 120 as part of acapability negotiation process. Alternatively, sink device 160 maytransmit information describing the third-party device to source device120, and based on the information, source device 120 can determine aunique identifier for the third-party device. The information describingthe third party device may, for example, include information to identifythe third-party device and/or information to identify capabilities ofthe third-party device. Regardless of whether the unique identifiers isdetermined by source device 120 or sink device 160, when sink device 160transmits data packets with user input obtained from the third partdevice, sink device 160 can include the unique identifier in the datapacket, in a payload header for example, so that source device 120 canidentify the origin of the user input.

If input category field 624 of data packet header 610 indicates yet adifferent input category, such as a voice command, then payload data 650can have yet a different input format. For a voice command, payload data650 may include coded audio. The codec for encoding and decoding theaudio of the voice command can be negotiated between source device 120and sink device 160 via a series of messages. For transmitting a voicecommand, timestamp field 626 may include a speech-sampling time value.In such an instance, timestamp flag 622 may be set to indicate atimestamp is present, but instead of a timestamp as described above,timestamp field 626 may include a speech-sampling time value for theencoded audio of payload data 650.

In some examples, a voice command may be transmitted as a genericcommand as described above, in which case input category field 624 maybe set to identify the generic command format, and one of the reservedgeneric IE IDs may be assigned to voice commands. If the voice commandis transmitted as a generic command, then a speech sampling rate may bepresent in timestamp field 626 of data packet header 610 or may bepresent in payload data 650.

For captured voice command data, the voice data can be encapsulated inmultiple ways. For example, the voice command data can be encapsulatedusing RTP which can provide the payload type to identify the codec andtimestamp, with the timestamp being used to identify the sampling rate.The RTP data can be encapsulated using the generic user input formatdescribed above, either with or without the optional timestamp. Sinkdevice 160 can transmit the generic input data that carries the voicecommand data to source device 120 using TPC/IP.

As discussed previously, when coordinates are included as part of a datapacket such as data packet 600, in payload data 650 for example, thecoordinates may correspond to coordinates scaled based on a negotiatedresolution, display window coordinates, normalized coordinates, orcoordinates associated with a sink display. In some instances,additional information, may be included, either in the data packet ortransmitted separately, for use by a source device to normalizecoordinates received in the data packet.

Regardless of the input category for a particular data packet the datapacket header may be an application layer packet header, and the datapacket may be transmitted over TCP/IP. TCP/IP can enable sink device 160and source device 120 to perform retransmission techniques in the eventof packet loss. The data packet may be sent from sink device 160 tosource device 120 to control audio data or video data of source device120 or for other purposes such as to control an application running onsource device 120.

FIG. 7A is a flowchart of an example method of negotiating capabilitiesbetween a sink device and a source device. The illustrated examplemethod may be performed by sink device 160 (FIG. 1A) or 360 (FIG. 3). Insome examples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in one or more of the flow charts describedherein.

The method of FIG. 7A includes sink device 160 receiving from the sourcedevice 120 a first message (701). The message may, for example, comprisea get parameter request. In response to the first message, sink device160 may send a second message to source device 120 (703). The secondmessage may, for example, comprise a get parameter response thatidentifies a first list of supported input categories and a plurality offirst lists of supported types, wherein each of the supported inputcategories of the first list of supported input categories has anassociated first list of supported types. The supported input categoriesmay, for example, correspond to the same categories used for inputcategory field 624 of FIG. 6. Table 2 above represents one example ofsupported types for a particular input category (generic inputs in thisexample). Sink device 160 may receive from source device 120, a thirdmessage (705). The third message may, for example, comprise a setparameter request, wherein the set parameter request identifies a portfor communication, a second list of supported input categories, and aplurality of second lists of supported types, with each of the supportedinput categories of the second list of supported input categories havingan associated second list of supported types, and each of the supportedtypes of the second lists including a subset of the types of the firstlists. Sink device 160 can transmit to source device 120 a fourthmessage (707). The fourth message may, for example, comprise a setparameter response to confirm that the types of the second lists havebeen enabled. Sink device 160 can receive from source device 120 a fifthmessage (709). The fifth message may, for example, comprise a second setparameter request that indicates that a communication channel betweenthe source device 120 and sink device 160 has been enabled. Thecommunication channel may, for example, comprise a user input backchannel (UIBC). Sink device 160 can transmit to source device 120 asixth message (711). The sixth message may, for example, comprise asecond set parameter response that confirms receipt of the second setparameter request by sink device 160.

FIG. 7B is a flowchart of an example method of negotiating capabilitiesbetween a sink device and a source device. The illustrated examplemethod may be performed by source device 120 (FIG. 1A) or 220 (FIG. 2).In some examples, a computer-readable storage medium (e.g., memory 232)may store instructions, modules, or algorithms that, when executed,cause one or more processors (e.g., processor 231) to perform one ormore of the illustrated steps in the flow chart.

The method of FIG. 7B includes source device 120 transmitting to sinkdevice 160 a first message (702). The first message may, for example,comprise a get parameter request. Source device 120 can receive a secondmessage from sink device 160 (704). The second message may, for example,comprise a get parameter response that identifies a first list ofsupported input categories and a plurality of first lists of supportedtypes, wherein each of the supported input categories of the first listof supported input categories has an associated first list of supportedtypes. Source device 120 may transmit to sink device 160, a thirdmessage (706). The third message may, for example, comprise a setparameter request that identifies a port for communication, a secondlist of supported input categories, and a plurality of second lists ofsupported types, with each of the supported input categories of thesecond list of supported input categories having an associated secondlist of supported types, and each of the supported types of the secondlists including a subset of the types of the first lists. Source device120 can receive from sink device 160 a fourth message (708). The fourthmessage may, for example, comprise a set parameter response to confirmthat the types of the second lists have been enabled. Source device 120can transmit to sink device 160 a fifth message (710). The fifth messagemay, for example, comprise a second set parameter request that indicatesthat a communication channel between the source device 120 and sinkdevice 160 has been enabled. The communication channel may, for example,comprise a user input back channel (UIBC). Source device 120 can receivefrom sink device 160 a sixth message (712). The sixth message may, forexample, comprise a second set parameter response that confirms receiptof the second set parameter request by sink device 160.

FIG. 8A is a flow chart of an example method of transmitting user inputdata from a wireless sink device to a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by sink device 160 (FIG. 1A) or 360 (FIG. 3). In someexamples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 8A includes obtaining user input data at a wirelesssink device, such as wireless sink device 160 (801). The user input datamay be obtained through a user input component of wireless sink device160 such as, for example, user input interface 376 shown in relation towireless sink device 360. Additionally, sink device 160 may categorizethe user input data as, for example, generic, forwarded, or operatingsystem specific. Sink device 160 may then generate a data packet headerbased on the user input data (803). The data packet header can be anapplication layer packet header. The data packet header may comprise,among other fields, a field to identify an input category correspondingto the user input data. The input category may comprise, for example, ageneric input format or a human interface device command. Sink device160 may further generate a data packet (805), where the data packetcomprises the generated data packet header and payload data. In oneexample, payload data may include received user input data and mayidentify one or more user commands. Sink device 160 may then transmitthe generated data packet (807) to the wireless source device (e.g.,source device 120 of FIG. 1A or 220 of FIG. 2). Sink device 160 maycomprise components that allow transfer of data packets, includingtransport unit 333 and wireless modem 334 as shown in FIG. 3, forexample. Sink device 160 may transfer the data packet over TCP/IP.

FIG. 8B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 8B includes receiving a data packet (802), where thedata packet may comprise, among other things, a data packet header andpayload data. Payload data may include, for example, user input data.Source device 120 may comprise communications components that allowtransfer of data packets, including transport unit 233 and wirelessmodem 234, for example as shown in reference to FIG. 2. Source device120 may then parse the data packet header (804) included in the datapacket, to determine an input category associated with the user inputdata contained in the payload data. Source device 120 may process thepayload data based on the determined input category (806). The datapackets described with reference to FIGS. 8A and 8B may generally takethe form of the data packets described with reference to FIG. 6 and maybe used to control audio/video data and applications at a source device.

FIG. 9A is a flow chart of an example method of transmitting user inputdata from a wireless sink device to a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by sink device 160 (FIG. 1A) or 360 (FIG. 3). In someexamples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 9A includes obtaining user input data at a wirelesssink device such as wireless sink device 160 (901). The user input datamay be obtained through a user input component of wireless sink device160 such as, for example, user input interface 376 shown with referenceto FIG. 3. Sink device 160 may then generate payload data (903), wherethe payload data may describe the user input data. In one example,payload data may include received user input data and may identify oneor more user commands. Sink device 160 may further generate a datapacket (905), where the data packet comprises a data packet header andthe generated payload data. Sink device 160 may then transmit thegenerated data packet (907) to the wireless source device (e.g., sourcedevice 120 of FIG. 1A or 220 of FIG. 2). Sink device 160 may comprisecomponents that allow transfer of data packets, such as transport unit333 and wireless modem 334, for example. The data packet can betransmitted to a wireless source device over TCP/IP.

FIG. 9B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 9B includes receiving a data packet from sink device360 (902), where the data packet may comprise, among other things, adata packet header and payload data. In one example, payload data maycomprise, for example, data describing details of a user input such asinput type value. Source device 120 may comprise communicationscomponents that allow transfer of data packets, including transport unit233 and wireless modem 234, for example as shown with reference to FIG.2. Source device 120 may then parse the data packet (904) to determinean input type value in an input type field in the payload data. Sourcedevice 120 may process the data describing details of the user inputbased on the determined input type value (906). The data packetsdescribed with reference to FIGS. 9A and 9B may generally take the formof the data packets described with reference to FIG. 6.

FIG. 10A is a flow chart of an example method of transmitting user inputdata from a wireless sink device to a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by sink device 160 (FIG. 1A) or 360 (FIG. 3). In someexamples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 10A includes obtaining user input data at a wirelesssink device, such as wireless sink device 160 (1001). The user inputdata may be obtained through a user input component of wireless sinkdevice 160 such as, for example, user input interface 376 as shown withreference to FIG. 3. Sink device 160 may then generate a data packetheader based on the user input (1003). The data packet header maycomprise, among other fields, a timestamp flag (e.g., a 1-bit field) toindicate if a timestamp field is present in the data packet header. Thetimestamp flag may, for example, include a “1” to indicate timestampfield is present and may include a “0” to indicate timestamp field isnot present. The timestamp field may be, for example, a 16-bit fieldcontaining a timestamp generated by source device 120 and added to videodata prior to transmission. Sink device 160 may further generate a datapacket (1005), where the data packet comprises the generated data packetheader and payload data. In one example, payload data may includereceived user input data and may identify one or more user commands.Sink device 160 may then transmit the generated data packet (1007) tothe wireless source device (e.g., source device 120 of FIG. 1A or 220 ofFIG. 2). Sink device 160 may comprise components that allow transfer ofdata packets, including transport unit 333 and wireless modem 334, forexample as shown in reference to FIG. 3. The data packet can betransmitted to a wireless source device over TCP/IP.

FIG. 10B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 10B includes receiving a data packet from wirelesssink device 160 (1002), where the data packet may comprise, among otherthings, a data packet header and payload data. Payload data may include,for example, user input data. Source device 120 may comprisecommunications components that allow transfer of data packets, includingtransport unit 233 and wireless modem 234, for example as shown inreference to FIG. 2. Source device 120 may then parse the data packetheader (1004) included in the data packet. Source device 120 maydetermine if a timestamp field is present in the data packet header(1006). In one example, Source device 120 may make the determinationbased on a timestamp flag value included in the data packet header. Ifthe data packet header includes a timestamp field, Source device 120 mayprocess the payload data based on a timestamp that is in the timestampfield (1008). The data packets described with reference to FIGS. 10A and10B may generally take the form of the data packets described withreference to FIG. 6 and may be used to control audio/video data at asource device.

FIG. 11A is a flow chart of an example method of transmitting user inputdata from a wireless sink device to a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by sink device 160 (FIG. 1A) or 360 (FIG. 3). In someexamples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 11A includes obtaining user input data at a wirelesssink device, such as wireless sink device 160 (1101). The user inputdata may be obtained through a user input component of wireless sinkdevice 160 such as, for example, user input interface 376 shown inreference to FIG. 3. Sink device 160 may then generate a data packetheader based on the user input (1103). The data packet header maycomprise, among other fields, a timestamp field. The timestamp field maycomprise, for example, a 16-bit field containing a timestamp based onmultimedia data that was generated by wireless source device 120 andtransmitted to wireless sink device 160. The timestamp may have beenadded to the frame of video data by wireless source device 120 prior tobeing transmitted to the wireless sink device. The timestamp field may,for example, identify a timestamp associated with a frame of video databeing displayed at wireless sink device 160 at the time the user inputdata was captured. Sink device 160 may further generate a data packet(1105), where the data packet comprises the generated data packet headerand payload data. In one example, payload data may include received userinput data and may identify one or more user commands. Sink device 160may then transmit the generated data packet (1107) to the wirelesssource device (e.g., source device 120 of FIG. 1A or 220 of FIG. 2).Sink device 160 may comprise components that allow transfer of datapackets, including transport unit 333 and wireless modem 334, forexample as shown in reference to FIG. 3. The data packet can betransmitted to a wireless source device over TCP/IP.

FIG. 11B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 11B includes receiving a data packet from a wirelesssink device, such as wireless sink device 160 (1102), where the datapacket may comprise, among other things, a data packet header andpayload data. Payload data may include, for example, user input data.Source device 120 may comprise communications components that allowtransfer of data packets, including transport unit 233 and wirelessmodem 234, for example as shown in reference to FIG. 2. Source device120 may then identify a timestamp field in the data packet header(1104). Source device 120 may process the payload data based on atimestamp that is in the timestamp field (1106). As part of processingthe payload data, based on the timestamp, source device 120 may identifya frame of video data being displayed at the wireless sink device at thetime the user input data was obtained and interpret the payload databased on content of the frame. As part of processing the payload databased on the timestamp, source device 120 may compare the timestamp to acurrent timestamp for a current frame of video being transmitted bysource device 120 and may perform a user input command described in thepayload data in response to a time difference between the timestamp andthe current timestamp being less than a threshold value, or not performa user input command described in the payload data in response to a timedifference between the timestamp and the current timestamp being greaterthan a threshold value. The data packets described with reference toFIGS. 11A and 11B may generally take the form of the data packetsdescribed with reference to FIG. 6 and may be used to controlaudio/video data at a source device.

FIG. 12A is a flow chart of an example method of transmitting user inputdata from a wireless sink device to a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by sink device 160 (FIG. 1A) or 360 (FIG. 3). In someexamples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 12A includes obtaining user input data at a wirelesssink device, such as wireless sink device 160 (1201). In one example,the user input data may be voice command data, which may be obtainedthrough a user input component of wireless sink device 160 such as, forexample, a voice command recognition module included in user inputinterface 376 in FIG. 3. Sink device 160 may generate a data packetheader based on the user input (1203). Sink device 160 may also generatepayload data (1205), where the payload data may comprise the voicecommand data. In one example, payload data may also include receiveduser input data and may identify one or more user commands. Sink device160 may further generate a data packet (1207), where the data packetcomprises the generated data packet header and payload data. Sink device160 may then transmit the generated data packet (1209) to the wirelesssource device (e.g., source device 120 of FIG. 1A or 220 of FIG. 2).Sink device 160 may comprise components that allow transfer of datapackets, including transport unit 333 and wireless modem 334, forexample as shown in reference to FIG. 3. The data packet can betransmitted to a wireless source device over TCP/IP.

FIG. 12B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 12B includes receiving a data packet (1202), wherethe data packet may comprise, among other things, a data packet headerand payload data. Payload data may include, for example, user input datasuch as voice command data. Source device 120 may comprisecommunications components that allow transfer of data packets, includingtransport unit 233 and wireless modem 234, for example as shown inreference to FIG. 2. Source device 120 may then parse the payload data(1204) included in the data packet, to determine if the payload datacomprises voice command data. The data packets described with referenceto FIGS. 12A and 12B may generally take the form of the data packetsdescribed with reference to FIG. 6 and may be used to controlaudio/video data at a source device.

FIG. 13A is a flow chart of an example method of transmitting user inputdata from a wireless sink device to a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by sink device 160 (FIG. 1A) or 360 (FIG. 3). In someexamples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 13A includes obtaining user input data at a wirelesssink device, such as wireless sink device 160 (1301). In one example,the user input data may be a multi-touch gesture, which may be obtainedthrough a user input component of wireless sink device 160 such as, forexample, UI 167 or user input interface 376 of FIG. 3. In one example,the multi-touch gesture may comprise a first touch input and a secondtouch input. Sink device 160 may generate a data packet header based onthe user input (1303). Sink device 160 may also generate payload data(1305), where the payload data may associate user input data for thefirst touch input event with a first pointer identification and userinput data for the second touch input event with a second pointeridentification. Sink device 160 may further generate a data packet(1307), where the data packet comprises the generated data packet headerand payload data. Sink device 160 may then transmit the generated datapacket (1309) to the wireless source device (e.g., source device 120 ofFIG. 1A or 220 of FIG. 2). Sink device 160 may comprise components thatallow transfer of data packets, including transport unit 333 andwireless modem 334, for example as shown in reference to FIG. 3. Thedata packet can be transmitted to a wireless source device over TCP/IP.

FIG. 13B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 13B includes receiving a data packet (1302), wherethe data packet may comprise, among other things, a data packet headerand payload data. Payload data may include, for example, user input datasuch as multi-touch gesture. Source device 120 may comprisecommunications components that allow transfer of data packets, includingtransport unit 233 and wireless modem 234, for example as shown in FIG.2. Source device 120 may then parse the payload data (1304) included inthe data packet, to identify user input data included in the payloaddata. In one example, the identified data may include user input datafor a first touch input event with a first pointer identification anduser input data for a second touch input event with a second pointeridentification. Source device 120 may then interpret the user input datafor the first touch input event and the user input data for the secondtouch input event as a multi-touch gesture (1306). The data packetsdescribed with reference to FIGS. 13A and 13B may generally take theform of the data packets described with reference to FIG. 6 and may beused to control audio/video data at a source device.

FIG. 14A is a flow chart of an example method of transmitting user inputdata from a wireless sink device to a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by sink device 160 (FIG. 1A) or 360 (FIG. 3). In someexamples, a computer-readable storage medium (e.g., memory 332) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 331) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 14A includes obtaining user input data at wirelesssink device 360 from an external device (1401). In one example, theexternal device may be a third party device connected to the sinkdevice. Sink device 160 may generate a data packet header based on theuser input (1403). In one example, the data packet header may identifythe user input data as forwarded user input data. Sink device 160 mayalso generate payload data (1405), where the payload data may comprisethe user input data. Sink device 160 may further generate a data packet(1407), where the data packet may comprise the generated data packetheader and payload data. Sink device 160 may then transmit the generateddata packet (1409) to the wireless source device (e.g., source device120 of FIG. 1A or 220 of FIG. 2). Sink device 160 may comprisecomponents that allow transfer of data packets, including transport unit333 and wireless modem 334, for example as shown with reference to FIG.3. The data packet can be transmitted to a wireless source device overTCP/IP.

FIG. 14B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 14B includes receiving a data packet (1402), wherethe data packet may comprise, among other things, a data packet headerand payload data. Payload data may include, for example, user input datasuch as a forwarded user input command indicating user input data wasforwarded from a third party device. Source device 120 may comprisecommunications components that allow transfer of data packets, includingtransport unit 233 and wireless modem 234, for example as shown inreference to FIG. 2. Source device 120 may then parse the data packetheader and may determine that the payload data comprises a forwardeduser input command (1404). Source device 120 may then parse the payloaddata (1406) included in the data packet, to identify an identificationassociated with the third party device corresponding to the forwardeduser input command. Source device 120 may then process the payload databased on the identified identification of the third party device (1408).The data packets described with reference to FIGS. 14A and 14B maygenerally take the form of the data packets described with reference toFIG. 6 and may be used to control audio/video data at a source device.

FIG. 15A is a flow chart of an example method of transmitting user datafrom a wireless sink device to a wireless source device in accordancewith this disclosure. The illustrated example method may be performed bysink device 160 (FIG. 1A) or 360 (FIG. 3). In some examples, acomputer-readable storage medium (e.g., memory 332) may storeinstructions, modules, or algorithms that, when executed, cause one ormore processors (e.g., processor 331) to perform one or more of theillustrated steps in the flow chart.

The method of FIG. 15A includes obtaining user input data at thewireless sink device (1501). The user input data can have associatedcoordinate data. The associated coordinate data may, for example,corresponds to a location of a mouse click event or a location of atouch event. Sink device 160 may then normalize the associatedcoordinate data to generate normalized coordinate data (1503). Sinkdevice 160 may then generate a data packet that includes the normalizedcoordinate data (1505). Normalizing the coordinate data can includescaling the associated coordinate data based on a ratio of theresolution of a display window and a resolution of the display of thesource, such as display 22 of source device 120. The resolution of thedisplay window can be determined by sink device 160, and the resolutionof the display of the source device can be received from source device120. Sink device 160 may then transmit the data packet with thenormalized coordinates to wireless source device 120 (1507). As part ofthe method of FIG. 15A, sink device 160 may also determine if theassociated coordinate data is within a display window for content beingreceived from the wireless source device, and for example, process auser input locally if the associated coordinate data is outside thedisplay window, or otherwise normalize the coordinates as described ifthe input is within the display window.

FIG. 15B is a flow chart of an example method of receiving user inputdata from a wireless sink device at a wireless source device inaccordance with this disclosure. The illustrated example method may beperformed by source device 120 (FIG. 1A) or 220 (FIG. 2). In someexamples, a computer-readable storage medium (e.g., memory 232) maystore instructions, modules, or algorithms that, when executed, causeone or more processors (e.g., processor 231) to perform one or more ofthe illustrated steps in the flow chart.

The method of FIG. 15B includes receiving a data packet at the wirelesssource device, where the data packet comprises user input data withassociated coordinate data (1502). The associated coordinate data may,for example, corresponds to a location of a mouse click event or alocation of a touch event at a sink device. Source device 120 may thennormalize the associated coordinate data to generate normalizedcoordinate data (1504). Source device 120 can normalize the coordinatedata by scaling the associated coordinate data based on a ratio of theresolution of the display window and a resolution of the display of thesource. Source device 120 can determine the resolution of the display ofthe source device and can receive the resolution of the display windowfrom the wireless sink device. Source device may then process the datapacket based o the normalized coordinate data (1506). The data packetsdescribed with reference to FIGS. 15A and 15B may generally take theform of the data packets described with reference to FIG. 6 and may beused to control audio/video data at a source device.

For simplicity of explanation, aspects of this disclosure have beendescribed separately with reference to FIGS. 7-15. It is contemplated,however, that these various aspects can be combined and used inconjunction with one another and not just separately. Generally,functionality and/or modules described herein may be implemented ineither or both of the wireless source device and wireless sink device.In this way, user interface capabilities described in the currentexample may be used interchangeably between the wireless source deviceand wireless sink device.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, and integratedcircuit (IC) or a set of ICs (i.e., a chip set). Any components, modulesor units have been described provided to emphasize functional aspectsand does not necessarily require realization by different hardwareunits.

Accordingly, the techniques described herein may be implemented inhardware, software, firmware, or any combination thereof. If implementedin hardware, any features described as modules, units or components maybe implemented together in an integrated logic device or separately asdiscrete but interoperable logic devices. If implemented in software,the techniques may be realized at least in part by a computer-readablemedium comprising instructions that, when executed in a processor,performs one or more of the methods described above. Thecomputer-readable medium may comprise a tangible and non-transitorycomputer-readable storage medium and may form part of a computer programproduct, which may include packaging materials. The computer-readablestorage medium may comprise random access memory (RAM) such assynchronous dynamic random access memory (SDRAM), read-only memory(ROM), non-volatile random access memory (NVRAM), electrically erasableprogrammable read-only memory (EEPROM), FLASH memory, magnetic oroptical data storage media, and the like. The techniques additionally,or alternatively, may be realized at least in part by acomputer-readable communication medium that carries or communicates codein the form of instructions or data structures and that can be accessed,read, and/or executed by a computer.

The code may be executed by one or more processors, such as one or moredigital signal processors (DSPs), general purpose microprocessors, anapplication specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated software modules or hardware modules configured for encodingand decoding, or incorporated in a combined video codec. Also, thetechniques could be fully implemented in one or more circuits or logicelements.

Various aspects of the disclosure have been described. These and otheraspects are within the scope of the following claims.

The invention claimed is:
 1. A method of negotiating capabilitiesbetween a wireless sink device and a wireless source device, the methodcomprising: transmitting a message to the wireless source device,wherein the message identifies: a list of supported input categories,wherein the list of supported input categories identifies formats ofuser input data supported by the wireless sink device; and, a pluralityof lists of supported types, wherein each of the supported inputcategories of the list of supported input categories has an associatedlist of supported types.
 2. The method of claim 1, wherein the messageis an RTSP GET_PARAMETER response message.
 3. The method of claim1,further comprising: wherein the list of supported input categories isa first list of supported input categories, and wherein the plurality oflists of supported types is a first plurality of lists of supportedtypes; and, receiving from the wireless source device a second message,wherein the second message identifies: a second list of supported inputcategories; a plurality of second lists of supported types, wherein eachof the supported input categories of the second list of supported inputcategories has an associated second list of supported types.
 4. Themethod of claim 3, wherein the second message further comprises a portfor communication.
 5. The method of claim 3, wherein the second messageis an RTSP SET_PARAMETER request message.
 6. The method of claim 3,wherein the supported types of the second lists are a subset of thetypes of the first lists.
 7. The method of claim 3, further comprising:transmitting to the wireless source device, a third message to confirmthat the types of the second lists have been enabled.
 8. The method ofclaim 7, further comprising: receiving from the wireless source device,a fourth message, wherein the fourth message indicates that acommunication channel between the wireless source device and thewireless sink device has been enabled.
 9. The method of claim 8, furthercomprising: transmitting to the wireless source device, a fifth message,wherein the fifth message confirms receipt of the fourth message by thewireless sink device.
 10. The method of claim 8, wherein thecommunication channel is a user input back channel (UIBC).
 11. Themethod of claim 1, wherein the supported input categories of the list ofsupported input categories are selected from a group consisting of ageneric command and a human-interface device command (HIDC).
 12. Themethod of claim 1, further comprising: receiving from the wirelesssource device a parameter request message, wherein the parameter requestmessage identifies an input path for a supported type of the list ofsupported types.
 13. The method of claim 1, wherein the supported typesof the lists of supported types are selected from a group consisting ofa keyboard, a mouse, a single touch, a multi touch, a joystick, acamera, a gestures, and a remote control.
 14. The method of claim 2,wherein the supported types of the second lists of supported types areselected from a group consisting of a keyboard, a mouse, a single touch,a multi touch, a joystick, a camera, a gestures, and a remote control.15. The method of claim 4, wherein the port for communication is atransmission control protocol (TCP) port.
 16. The method of claim 1,wherein the first message further identifies a null entry for asupported input category to indicate that the input category is notsupported by the wireless sink device.
 17. The method of claim 1,wherein the first message is a text format message.
 18. A wireless sinkdevice configured to negotiate capabilities with a wireless sourcedevice, the wireless sink device comprising: a memory storinginstructions; one or more processors configured to execute theinstructions, wherein upon execution of the instructions the one or moreprocessors cause: transmitting a message to the wireless source device,wherein the message identifies: a list of supported input categories,wherein the list of supported input categories identifies formats ofuser input data supported by the wireless sink device; and, a pluralityof lists of supported types, wherein each of the supported inputcategories of the list of supported input categories has an associatedlist of supported types.
 19. The device of claim 18, wherein the messageis an RTSP GET_PARAMETER response message.
 20. The device of claim 18,wherein the list of supported input categories is a first list ofsupported input categories, and wherein the plurality of lists ofsupported types is a first plurality of lists of supported types; and,wherein upon execution of the instructions the one or more processorsfurther cause: receiving from the wireless source device a secondmessage, wherein the second message identifies: a second list ofsupported input categories; a plurality of second lists of supportedtypes, wherein each of the supported input categories of the second listof supported input categories has an associated second list of supportedtypes.
 21. The device of claim 20, wherein the second message furthercomprises a port for communication.
 22. The device of claim 20, whereinthe second message is an RTSP SET_PARAMETER request message.
 23. Thedevice of claim 20, wherein the supported types of the second lists area subset of the types of the first lists.
 24. The device of claim 20,wherein upon execution of the instructions the one or more processorsfurther cause: transmitting to the wireless source device, a thirdmessage to confirm that the types of the second lists have been enabled.25. The device of claim 24, wherein upon execution of the instructionsthe one or more processors further cause: receiving from the wirelesssource device, a fourth message, wherein the fourth message indicatesthat a communication channel between the wireless source device and thewireless sink device has been enabled.
 26. The device of claim 25,wherein upon execution of the instructions the one or more processorsfurther cause: transmitting to the wireless source device, a fifthmessage, wherein the fifth message confirms receipt of the fourthmessage by the wireless sink device.
 27. The device of claim 25, whereinthe communication channel is a user input back channel (UIBC).
 28. Thedevice of claim 18, wherein the supported input categories of the listof supported input categories are selected from a group consisting of ageneric command and a human-interface device command (HIDC).
 29. Thedevice of claim 18, wherein upon execution of the instructions the oneor more processors further cause: receiving from the wireless sourcedevice a parameter request message, wherein the parameter requestmessage identifies an input path for a supported type of the list ofsupported types.
 30. The device of claim 18, wherein the supported typesof the lists of supported types are selected from a group consisting ofa keyboard, a mouse, a single touch, a multi touch, a joystick, acamera, a gestures, and a remote control.
 31. The device of claim 19,wherein the supported types of the second lists of supported types areselected from a group consisting of a keyboard, a mouse, a single touch,a multi touch, a joystick, a camera, a gestures, and a remote control.32. The device of claim 21, wherein the port for communication is atransmission control protocol (TCP) port.
 33. The device of claim 18,wherein the first message further identifies a null entry for asupported input category to indicate that the input category is notsupported by the wireless sink device.
 34. The device of claim 18,wherein the first message is a text format message.
 35. Acomputer-readable storage medium storing instructions that uponexecution by one or more processors cause the one or more processors toperform a method of negotiating capabilities between a wireless sinkdevice and a wireless source device, the method comprising: transmittinga message to the wireless source device, wherein the message identifies:a list of supported input categories, wherein the list of supportedinput categories identifies formats of user input data supported by thewireless sink device; and, a plurality of lists of supported types,wherein each of the supported input categories of the list of supportedinput categories has an associated list of supported types.
 36. Awireless sink device configured to negotiate capabilities with awireless source device, the wireless sink device comprising: means fortransmitting a message to the wireless source device, wherein themessage identifies: a list of supported input categories, wherein thelist of supported input categories identifies formats of user input datasupported by the wireless sink device; and, a plurality of lists ofsupported types, wherein each of the supported input categories of thelist of supported input categories has an associated list of supportedtypes.
 37. A method of negotiating capabilities between a wireless sinkdevice and a wireless source device, the method comprising: receiving amessage from the wireless sink device, wherein the message identifies: alist of supported input categories, wherein the list of supported inputcategories identifies formats of user input data supported by thewireless sink device; and, a plurality of lists of supported types,wherein each of the supported input categories of the list of supportedinput categories has an associated list of supported types.
 38. Themethod of claim 37, wherein the message is an RTSP GET_PARAMETERresponse message.
 39. The method of claim 37, further comprising:wherein the list of supported input categories is a first list ofsupported input categories, and wherein the plurality of lists ofsupported types is a first plurality of lists of supported types; and,transmitting to the wireless sink device a second message, wherein thesecond message identifies: a second list of supported input categories;a plurality of second lists of supported types, wherein each of thesupported input categories of the second list of supported inputcategories has an associated second list of supported types.
 40. Themethod of claim 39, wherein the second message further comprises a portfor communication.
 41. The method of claim 39, wherein the secondmessage is an RTSP SET_PARAMETER request message.
 42. The method ofclaim 39, wherein the supported types of the second lists are a subsetof the types of the first lists.
 43. The method of claim 39, furthercomprising: receiving from the wireless sink device, a third message toconfirm that the types of the second lists have been enabled.
 44. Themethod of claim 43, further comprising: transmitting to the wirelesssink device, a fourth message, wherein the fourth message indicates Thata communication channel between the wireless source device and thewireless sink device has been enabled.
 45. The method of claim 44,further comprising: receiving from the wireless sink device, a fifthmessage, wherein the fifth message confirms receipt of the fourthmessage by the wireless sink device.
 46. The method of claim 44, whereinthe communication channel is a user input back channel (UIBC).
 47. Themethod of claim 37, wherein the supported input categories of the listof supported input categories are selected from a group consisting of ageneric command and a human-interface device command (HIDC).
 48. Themethod of claim 37, further comprising: transmitting to the wirelesssink device a parameter request message, wherein the parameter requestmessage identifies an input path for a supported type of the list ofsupported types.
 49. The method of claim 37, wherein the supported typesof the lists of supported types are selected from a group consisting ofa keyboard, a mouse, a single touch, a multi touch, a joystick, acamera, a gestures, and a remote control.
 50. The method of claim 39,wherein the supported types of the second lists of supported types areselected from a group consisting of a keyboard, a mouse, a single touch,a multi touch, a joystick, a camera, a gestures, and a remote control.51. The method of claim 40, wherein the port for communication is atransmission control protocol (TCP) port.
 52. The method of claim 37,wherein the first message further identifies a null entry for asupported input category to indicate that the input category is notsupported by the wireless sink device.
 53. The method of claim 37,wherein the first message is a text format message.
 54. A wirelesssource device configured to negotiate capabilities with a wireless sinkdevice, the wireless source device comprising: a memory storinginstructions; one or more processors configured to execute theinstructions, wherein upon execution of the instructions the one or moreprocessors cause: receiving a message from the wireless sink device,wherein the message identifies: a list of supported input categories,wherein the list of supported input categories identifies formats ofuser input data supported by the wireless sink device; and, a pluralityof lists of supported types, wherein each of the supported inputcategories of the list of supported input categories has an associatedlist of supported types.
 55. The wireless source device of claim 54,wherein the message is an RTSP GET_PARAMETER response message.
 56. Thewireless source device of claim 54, wherein the list of supported inputcategories is a first list of supported input categories, and whereinthe plurality of lists of supported types is a first plurality of listsof supported types; and, wherein upon execution of the instructions theone or more processors further cause: transmitting to the wireless sinkdevice a second message, wherein the second message identifies: a secondlist of supported input categories; a plurality of second lists ofsupported types, wherein each of the supported input categories of thesecond list of supported input categories has an associated second listof supported types.
 57. The wireless source device of claim 56, whereinthe second message further comprises a port for communication.
 58. Thewireless source device of claim 56, wherein the second message is anRTSP SET_PARAMETER request message.
 59. The wireless source device ofclaim 56, wherein the supported types of the second lists are a subsetof the types of the first lists.
 60. The wireless source device of claim56, wherein upon execution of the instructions the one or moreprocessors further cause: receiving from the wireless sink device, athird message to confirm that the types of the second lists have beenenabled.
 61. The wireless source device of claim 60, wherein uponexecution of the instructions the one or more processors further cause:transmitting to the wireless sink device, a fourth message, wherein thefourth message indicates that a communication channel between thewireless source device and the wireless sink device has been enabled.62. The wireless source device of claim 61, wherein upon execution ofthe instructions the one or more processors further cause: receivingfrom the wireless sink device, a fifth message, wherein the fifthmessage confirms receipt of the fourth message by the wireless sinkdevice.
 63. The wireless source device of claim 61, wherein thecommunication channel is a user input back channel (UIBC).
 64. Thewireless source device of claim 54, wherein the supported inputcategories of the list of supported input categories are selected from agroup consisting of a generic command and a human-interface devicecommand (HIDC).
 65. The wireless source device of claim 54, wherein uponexecution of the instructions the one or more processors further cause:transmitting to the wireless sink device a parameter request message,wherein the parameter request message identifies an input path for asupported type of the list of supported types.
 66. The wireless sourcedevice of claim 54, wherein the supported types of the lists ofsupported types are selected from a group consisting of a keyboard, amouse, a single touch, a multi touch, a joystick, a camera, a gestures,and a remote control.
 67. The wireless source device of claim 56,wherein the supported types of the second lists of supported types areselected from a group consisting of a keyboard, a mouse, a single touch,a multi touch, a joystick, a camera, a gestures, and a remote control.68. The wireless source device of claim 58, wherein the port forcommunication is a transmission control protocol (TCP) port.
 69. Thewireless source device of claim 54, wherein the first message furtheridentifies a null entry for a supported input category to indicate thatthe input category is not supported by the wireless sink device.
 70. Thewireless source device of claim 54, wherein the first message is a textformat message.
 71. A non-transitory computer-readable storage mediumstoring instructions that upon execution by one or more processors causethe one or more processors to perform a method of negotiatingcapabilities between a wireless sink device and a wireless sourcedevice, the method comprising: receiving a message from the wirelesssink device, wherein the message identifies: a list of supported inputcategories, wherein the list of supported input categories identifiesformats of user input data supported by the wireless sink device; and, aplurality of lists of supported types, wherein each of the supportedinput categories of the list of supported input categories has anassociated list of supported types.
 72. A wireless source deviceconfigured to negotiate capabilities with a wireless sink device, thewireless source device comprising: means for receiving a message fromthe wireless sink device, wherein the message identifies: a list ofsupported input categories, wherein the list of supported inputcategories identifies formats of user input data supported by thewireless sink device; and, a plurality of lists of supported types,wherein each of the supported input categories of the list of supportedinput categories has an associated list of supported types.